2 * Copyright (C) 2007 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mount.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/parser.h>
37 #include <linux/ctype.h>
38 #include <linux/namei.h>
39 #include <linux/miscdevice.h>
40 #include <linux/magic.h>
41 #include <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/mnt_namespace.h>
44 #include <linux/ratelimit.h>
46 #include "delayed-inode.h"
49 #include "transaction.h"
50 #include "btrfs_inode.h"
52 #include "print-tree.h"
57 #include "compression.h"
59 #define CREATE_TRACE_POINTS
60 #include <trace/events/btrfs.h>
62 static const struct super_operations btrfs_super_ops
;
63 static struct file_system_type btrfs_fs_type
;
65 static const char *btrfs_decode_error(struct btrfs_fs_info
*fs_info
, int errno
,
72 errstr
= "IO failure";
75 errstr
= "Out of memory";
78 errstr
= "Readonly filesystem";
82 if (snprintf(nbuf
, 16, "error %d", -errno
) >= 0)
91 static void __save_error_info(struct btrfs_fs_info
*fs_info
)
94 * today we only save the error info into ram. Long term we'll
95 * also send it down to the disk
97 fs_info
->fs_state
= BTRFS_SUPER_FLAG_ERROR
;
101 * We move write_super stuff at umount in order to avoid deadlock
102 * for umount hold all lock.
104 static void save_error_info(struct btrfs_fs_info
*fs_info
)
106 __save_error_info(fs_info
);
109 /* btrfs handle error by forcing the filesystem readonly */
110 static void btrfs_handle_error(struct btrfs_fs_info
*fs_info
)
112 struct super_block
*sb
= fs_info
->sb
;
114 if (sb
->s_flags
& MS_RDONLY
)
117 if (fs_info
->fs_state
& BTRFS_SUPER_FLAG_ERROR
) {
118 sb
->s_flags
|= MS_RDONLY
;
119 printk(KERN_INFO
"btrfs is forced readonly\n");
124 * __btrfs_std_error decodes expected errors from the caller and
125 * invokes the approciate error response.
127 void __btrfs_std_error(struct btrfs_fs_info
*fs_info
, const char *function
,
128 unsigned int line
, int errno
)
130 struct super_block
*sb
= fs_info
->sb
;
135 * Special case: if the error is EROFS, and we're already
136 * under MS_RDONLY, then it is safe here.
138 if (errno
== -EROFS
&& (sb
->s_flags
& MS_RDONLY
))
141 errstr
= btrfs_decode_error(fs_info
, errno
, nbuf
);
142 printk(KERN_CRIT
"BTRFS error (device %s) in %s:%d: %s\n",
143 sb
->s_id
, function
, line
, errstr
);
144 save_error_info(fs_info
);
146 btrfs_handle_error(fs_info
);
149 static void btrfs_put_super(struct super_block
*sb
)
151 struct btrfs_root
*root
= btrfs_sb(sb
);
154 ret
= close_ctree(root
);
155 sb
->s_fs_info
= NULL
;
157 (void)ret
; /* FIXME: need to fix VFS to return error? */
161 Opt_degraded
, Opt_subvol
, Opt_subvolid
, Opt_device
, Opt_nodatasum
,
162 Opt_nodatacow
, Opt_max_inline
, Opt_alloc_start
, Opt_nobarrier
, Opt_ssd
,
163 Opt_nossd
, Opt_ssd_spread
, Opt_thread_pool
, Opt_noacl
, Opt_compress
,
164 Opt_compress_type
, Opt_compress_force
, Opt_compress_force_type
,
165 Opt_notreelog
, Opt_ratio
, Opt_flushoncommit
, Opt_discard
,
166 Opt_space_cache
, Opt_clear_cache
, Opt_user_subvol_rm_allowed
,
167 Opt_enospc_debug
, Opt_subvolrootid
, Opt_defrag
,
168 Opt_inode_cache
, Opt_no_space_cache
, Opt_recovery
,
169 Opt_check_integrity
, Opt_check_integrity_including_extent_data
,
170 Opt_check_integrity_print_mask
,
174 static match_table_t tokens
= {
175 {Opt_degraded
, "degraded"},
176 {Opt_subvol
, "subvol=%s"},
177 {Opt_subvolid
, "subvolid=%d"},
178 {Opt_device
, "device=%s"},
179 {Opt_nodatasum
, "nodatasum"},
180 {Opt_nodatacow
, "nodatacow"},
181 {Opt_nobarrier
, "nobarrier"},
182 {Opt_max_inline
, "max_inline=%s"},
183 {Opt_alloc_start
, "alloc_start=%s"},
184 {Opt_thread_pool
, "thread_pool=%d"},
185 {Opt_compress
, "compress"},
186 {Opt_compress_type
, "compress=%s"},
187 {Opt_compress_force
, "compress-force"},
188 {Opt_compress_force_type
, "compress-force=%s"},
190 {Opt_ssd_spread
, "ssd_spread"},
191 {Opt_nossd
, "nossd"},
192 {Opt_noacl
, "noacl"},
193 {Opt_notreelog
, "notreelog"},
194 {Opt_flushoncommit
, "flushoncommit"},
195 {Opt_ratio
, "metadata_ratio=%d"},
196 {Opt_discard
, "discard"},
197 {Opt_space_cache
, "space_cache"},
198 {Opt_clear_cache
, "clear_cache"},
199 {Opt_user_subvol_rm_allowed
, "user_subvol_rm_allowed"},
200 {Opt_enospc_debug
, "enospc_debug"},
201 {Opt_subvolrootid
, "subvolrootid=%d"},
202 {Opt_defrag
, "autodefrag"},
203 {Opt_inode_cache
, "inode_cache"},
204 {Opt_no_space_cache
, "nospace_cache"},
205 {Opt_recovery
, "recovery"},
206 {Opt_check_integrity
, "check_int"},
207 {Opt_check_integrity_including_extent_data
, "check_int_data"},
208 {Opt_check_integrity_print_mask
, "check_int_print_mask=%d"},
213 * Regular mount options parser. Everything that is needed only when
214 * reading in a new superblock is parsed here.
216 int btrfs_parse_options(struct btrfs_root
*root
, char *options
)
218 struct btrfs_fs_info
*info
= root
->fs_info
;
219 substring_t args
[MAX_OPT_ARGS
];
220 char *p
, *num
, *orig
= NULL
;
225 bool compress_force
= false;
227 cache_gen
= btrfs_super_cache_generation(root
->fs_info
->super_copy
);
229 btrfs_set_opt(info
->mount_opt
, SPACE_CACHE
);
235 * strsep changes the string, duplicate it because parse_options
238 options
= kstrdup(options
, GFP_NOFS
);
244 while ((p
= strsep(&options
, ",")) != NULL
) {
249 token
= match_token(p
, tokens
, args
);
252 printk(KERN_INFO
"btrfs: allowing degraded mounts\n");
253 btrfs_set_opt(info
->mount_opt
, DEGRADED
);
257 case Opt_subvolrootid
:
260 * These are parsed by btrfs_parse_early_options
261 * and can be happily ignored here.
265 printk(KERN_INFO
"btrfs: setting nodatasum\n");
266 btrfs_set_opt(info
->mount_opt
, NODATASUM
);
269 printk(KERN_INFO
"btrfs: setting nodatacow\n");
270 btrfs_set_opt(info
->mount_opt
, NODATACOW
);
271 btrfs_set_opt(info
->mount_opt
, NODATASUM
);
273 case Opt_compress_force
:
274 case Opt_compress_force_type
:
275 compress_force
= true;
277 case Opt_compress_type
:
278 if (token
== Opt_compress
||
279 token
== Opt_compress_force
||
280 strcmp(args
[0].from
, "zlib") == 0) {
281 compress_type
= "zlib";
282 info
->compress_type
= BTRFS_COMPRESS_ZLIB
;
283 } else if (strcmp(args
[0].from
, "lzo") == 0) {
284 compress_type
= "lzo";
285 info
->compress_type
= BTRFS_COMPRESS_LZO
;
291 btrfs_set_opt(info
->mount_opt
, COMPRESS
);
292 if (compress_force
) {
293 btrfs_set_opt(info
->mount_opt
, FORCE_COMPRESS
);
294 pr_info("btrfs: force %s compression\n",
297 pr_info("btrfs: use %s compression\n",
301 printk(KERN_INFO
"btrfs: use ssd allocation scheme\n");
302 btrfs_set_opt(info
->mount_opt
, SSD
);
305 printk(KERN_INFO
"btrfs: use spread ssd "
306 "allocation scheme\n");
307 btrfs_set_opt(info
->mount_opt
, SSD
);
308 btrfs_set_opt(info
->mount_opt
, SSD_SPREAD
);
311 printk(KERN_INFO
"btrfs: not using ssd allocation "
313 btrfs_set_opt(info
->mount_opt
, NOSSD
);
314 btrfs_clear_opt(info
->mount_opt
, SSD
);
315 btrfs_clear_opt(info
->mount_opt
, SSD_SPREAD
);
318 printk(KERN_INFO
"btrfs: turning off barriers\n");
319 btrfs_set_opt(info
->mount_opt
, NOBARRIER
);
321 case Opt_thread_pool
:
323 match_int(&args
[0], &intarg
);
325 info
->thread_pool_size
= intarg
;
326 printk(KERN_INFO
"btrfs: thread pool %d\n",
327 info
->thread_pool_size
);
331 num
= match_strdup(&args
[0]);
333 info
->max_inline
= memparse(num
, NULL
);
336 if (info
->max_inline
) {
337 info
->max_inline
= max_t(u64
,
341 printk(KERN_INFO
"btrfs: max_inline at %llu\n",
342 (unsigned long long)info
->max_inline
);
345 case Opt_alloc_start
:
346 num
= match_strdup(&args
[0]);
348 info
->alloc_start
= memparse(num
, NULL
);
351 "btrfs: allocations start at %llu\n",
352 (unsigned long long)info
->alloc_start
);
356 root
->fs_info
->sb
->s_flags
&= ~MS_POSIXACL
;
359 printk(KERN_INFO
"btrfs: disabling tree log\n");
360 btrfs_set_opt(info
->mount_opt
, NOTREELOG
);
362 case Opt_flushoncommit
:
363 printk(KERN_INFO
"btrfs: turning on flush-on-commit\n");
364 btrfs_set_opt(info
->mount_opt
, FLUSHONCOMMIT
);
368 match_int(&args
[0], &intarg
);
370 info
->metadata_ratio
= intarg
;
371 printk(KERN_INFO
"btrfs: metadata ratio %d\n",
372 info
->metadata_ratio
);
376 btrfs_set_opt(info
->mount_opt
, DISCARD
);
378 case Opt_space_cache
:
379 btrfs_set_opt(info
->mount_opt
, SPACE_CACHE
);
381 case Opt_no_space_cache
:
382 printk(KERN_INFO
"btrfs: disabling disk space caching\n");
383 btrfs_clear_opt(info
->mount_opt
, SPACE_CACHE
);
385 case Opt_inode_cache
:
386 printk(KERN_INFO
"btrfs: enabling inode map caching\n");
387 btrfs_set_opt(info
->mount_opt
, INODE_MAP_CACHE
);
389 case Opt_clear_cache
:
390 printk(KERN_INFO
"btrfs: force clearing of disk cache\n");
391 btrfs_set_opt(info
->mount_opt
, CLEAR_CACHE
);
393 case Opt_user_subvol_rm_allowed
:
394 btrfs_set_opt(info
->mount_opt
, USER_SUBVOL_RM_ALLOWED
);
396 case Opt_enospc_debug
:
397 btrfs_set_opt(info
->mount_opt
, ENOSPC_DEBUG
);
400 printk(KERN_INFO
"btrfs: enabling auto defrag");
401 btrfs_set_opt(info
->mount_opt
, AUTO_DEFRAG
);
404 printk(KERN_INFO
"btrfs: enabling auto recovery");
405 btrfs_set_opt(info
->mount_opt
, RECOVERY
);
407 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
408 case Opt_check_integrity_including_extent_data
:
409 printk(KERN_INFO
"btrfs: enabling check integrity"
410 " including extent data\n");
411 btrfs_set_opt(info
->mount_opt
,
412 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA
);
413 btrfs_set_opt(info
->mount_opt
, CHECK_INTEGRITY
);
415 case Opt_check_integrity
:
416 printk(KERN_INFO
"btrfs: enabling check integrity\n");
417 btrfs_set_opt(info
->mount_opt
, CHECK_INTEGRITY
);
419 case Opt_check_integrity_print_mask
:
421 match_int(&args
[0], &intarg
);
423 info
->check_integrity_print_mask
= intarg
;
424 printk(KERN_INFO
"btrfs:"
425 " check_integrity_print_mask 0x%x\n",
426 info
->check_integrity_print_mask
);
430 case Opt_check_integrity_including_extent_data
:
431 case Opt_check_integrity
:
432 case Opt_check_integrity_print_mask
:
433 printk(KERN_ERR
"btrfs: support for check_integrity*"
434 " not compiled in!\n");
439 printk(KERN_INFO
"btrfs: unrecognized mount option "
448 if (!ret
&& btrfs_test_opt(root
, SPACE_CACHE
))
449 printk(KERN_INFO
"btrfs: disk space caching is enabled\n");
455 * Parse mount options that are required early in the mount process.
457 * All other options will be parsed on much later in the mount process and
458 * only when we need to allocate a new super block.
460 static int btrfs_parse_early_options(const char *options
, fmode_t flags
,
461 void *holder
, char **subvol_name
, u64
*subvol_objectid
,
462 u64
*subvol_rootid
, struct btrfs_fs_devices
**fs_devices
)
464 substring_t args
[MAX_OPT_ARGS
];
465 char *device_name
, *opts
, *orig
, *p
;
473 * strsep changes the string, duplicate it because parse_options
476 opts
= kstrdup(options
, GFP_KERNEL
);
481 while ((p
= strsep(&opts
, ",")) != NULL
) {
486 token
= match_token(p
, tokens
, args
);
490 *subvol_name
= match_strdup(&args
[0]);
494 error
= match_int(&args
[0], &intarg
);
496 /* we want the original fs_tree */
499 BTRFS_FS_TREE_OBJECTID
;
501 *subvol_objectid
= intarg
;
504 case Opt_subvolrootid
:
506 error
= match_int(&args
[0], &intarg
);
508 /* we want the original fs_tree */
511 BTRFS_FS_TREE_OBJECTID
;
513 *subvol_rootid
= intarg
;
517 device_name
= match_strdup(&args
[0]);
522 error
= btrfs_scan_one_device(device_name
,
523 flags
, holder
, fs_devices
);
538 static struct dentry
*get_default_root(struct super_block
*sb
,
541 struct btrfs_root
*root
= sb
->s_fs_info
;
542 struct btrfs_root
*new_root
;
543 struct btrfs_dir_item
*di
;
544 struct btrfs_path
*path
;
545 struct btrfs_key location
;
551 * We have a specific subvol we want to mount, just setup location and
552 * go look up the root.
554 if (subvol_objectid
) {
555 location
.objectid
= subvol_objectid
;
556 location
.type
= BTRFS_ROOT_ITEM_KEY
;
557 location
.offset
= (u64
)-1;
561 path
= btrfs_alloc_path();
563 return ERR_PTR(-ENOMEM
);
564 path
->leave_spinning
= 1;
567 * Find the "default" dir item which points to the root item that we
568 * will mount by default if we haven't been given a specific subvolume
571 dir_id
= btrfs_super_root_dir(root
->fs_info
->super_copy
);
572 di
= btrfs_lookup_dir_item(NULL
, root
, path
, dir_id
, "default", 7, 0);
574 btrfs_free_path(path
);
579 * Ok the default dir item isn't there. This is weird since
580 * it's always been there, but don't freak out, just try and
581 * mount to root most subvolume.
583 btrfs_free_path(path
);
584 dir_id
= BTRFS_FIRST_FREE_OBJECTID
;
585 new_root
= root
->fs_info
->fs_root
;
589 btrfs_dir_item_key_to_cpu(path
->nodes
[0], di
, &location
);
590 btrfs_free_path(path
);
593 new_root
= btrfs_read_fs_root_no_name(root
->fs_info
, &location
);
594 if (IS_ERR(new_root
))
595 return ERR_CAST(new_root
);
597 if (btrfs_root_refs(&new_root
->root_item
) == 0)
598 return ERR_PTR(-ENOENT
);
600 dir_id
= btrfs_root_dirid(&new_root
->root_item
);
602 location
.objectid
= dir_id
;
603 location
.type
= BTRFS_INODE_ITEM_KEY
;
606 inode
= btrfs_iget(sb
, &location
, new_root
, &new);
608 return ERR_CAST(inode
);
611 * If we're just mounting the root most subvol put the inode and return
612 * a reference to the dentry. We will have already gotten a reference
613 * to the inode in btrfs_fill_super so we're good to go.
615 if (!new && sb
->s_root
->d_inode
== inode
) {
617 return dget(sb
->s_root
);
620 return d_obtain_alias(inode
);
623 static int btrfs_fill_super(struct super_block
*sb
,
624 struct btrfs_fs_devices
*fs_devices
,
625 void *data
, int silent
)
628 struct dentry
*root_dentry
;
629 struct btrfs_root
*tree_root
;
630 struct btrfs_key key
;
633 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
634 sb
->s_magic
= BTRFS_SUPER_MAGIC
;
635 sb
->s_op
= &btrfs_super_ops
;
636 sb
->s_d_op
= &btrfs_dentry_operations
;
637 sb
->s_export_op
= &btrfs_export_ops
;
638 sb
->s_xattr
= btrfs_xattr_handlers
;
640 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
641 sb
->s_flags
|= MS_POSIXACL
;
644 tree_root
= open_ctree(sb
, fs_devices
, (char *)data
);
646 if (IS_ERR(tree_root
)) {
647 printk("btrfs: open_ctree failed\n");
648 return PTR_ERR(tree_root
);
650 sb
->s_fs_info
= tree_root
;
652 key
.objectid
= BTRFS_FIRST_FREE_OBJECTID
;
653 key
.type
= BTRFS_INODE_ITEM_KEY
;
655 inode
= btrfs_iget(sb
, &key
, tree_root
->fs_info
->fs_root
, NULL
);
657 err
= PTR_ERR(inode
);
661 root_dentry
= d_alloc_root(inode
);
668 sb
->s_root
= root_dentry
;
670 save_mount_options(sb
, data
);
671 cleancache_init_fs(sb
);
675 close_ctree(tree_root
);
679 int btrfs_sync_fs(struct super_block
*sb
, int wait
)
681 struct btrfs_trans_handle
*trans
;
682 struct btrfs_root
*root
= btrfs_sb(sb
);
685 trace_btrfs_sync_fs(wait
);
688 filemap_flush(root
->fs_info
->btree_inode
->i_mapping
);
692 btrfs_start_delalloc_inodes(root
, 0);
693 btrfs_wait_ordered_extents(root
, 0, 0);
695 trans
= btrfs_start_transaction(root
, 0);
697 return PTR_ERR(trans
);
698 ret
= btrfs_commit_transaction(trans
, root
);
702 static int btrfs_show_options(struct seq_file
*seq
, struct vfsmount
*vfs
)
704 struct btrfs_root
*root
= btrfs_sb(vfs
->mnt_sb
);
705 struct btrfs_fs_info
*info
= root
->fs_info
;
708 if (btrfs_test_opt(root
, DEGRADED
))
709 seq_puts(seq
, ",degraded");
710 if (btrfs_test_opt(root
, NODATASUM
))
711 seq_puts(seq
, ",nodatasum");
712 if (btrfs_test_opt(root
, NODATACOW
))
713 seq_puts(seq
, ",nodatacow");
714 if (btrfs_test_opt(root
, NOBARRIER
))
715 seq_puts(seq
, ",nobarrier");
716 if (info
->max_inline
!= 8192 * 1024)
717 seq_printf(seq
, ",max_inline=%llu",
718 (unsigned long long)info
->max_inline
);
719 if (info
->alloc_start
!= 0)
720 seq_printf(seq
, ",alloc_start=%llu",
721 (unsigned long long)info
->alloc_start
);
722 if (info
->thread_pool_size
!= min_t(unsigned long,
723 num_online_cpus() + 2, 8))
724 seq_printf(seq
, ",thread_pool=%d", info
->thread_pool_size
);
725 if (btrfs_test_opt(root
, COMPRESS
)) {
726 if (info
->compress_type
== BTRFS_COMPRESS_ZLIB
)
727 compress_type
= "zlib";
729 compress_type
= "lzo";
730 if (btrfs_test_opt(root
, FORCE_COMPRESS
))
731 seq_printf(seq
, ",compress-force=%s", compress_type
);
733 seq_printf(seq
, ",compress=%s", compress_type
);
735 if (btrfs_test_opt(root
, NOSSD
))
736 seq_puts(seq
, ",nossd");
737 if (btrfs_test_opt(root
, SSD_SPREAD
))
738 seq_puts(seq
, ",ssd_spread");
739 else if (btrfs_test_opt(root
, SSD
))
740 seq_puts(seq
, ",ssd");
741 if (btrfs_test_opt(root
, NOTREELOG
))
742 seq_puts(seq
, ",notreelog");
743 if (btrfs_test_opt(root
, FLUSHONCOMMIT
))
744 seq_puts(seq
, ",flushoncommit");
745 if (btrfs_test_opt(root
, DISCARD
))
746 seq_puts(seq
, ",discard");
747 if (!(root
->fs_info
->sb
->s_flags
& MS_POSIXACL
))
748 seq_puts(seq
, ",noacl");
749 if (btrfs_test_opt(root
, SPACE_CACHE
))
750 seq_puts(seq
, ",space_cache");
752 seq_puts(seq
, ",nospace_cache");
753 if (btrfs_test_opt(root
, CLEAR_CACHE
))
754 seq_puts(seq
, ",clear_cache");
755 if (btrfs_test_opt(root
, USER_SUBVOL_RM_ALLOWED
))
756 seq_puts(seq
, ",user_subvol_rm_allowed");
757 if (btrfs_test_opt(root
, ENOSPC_DEBUG
))
758 seq_puts(seq
, ",enospc_debug");
759 if (btrfs_test_opt(root
, AUTO_DEFRAG
))
760 seq_puts(seq
, ",autodefrag");
761 if (btrfs_test_opt(root
, INODE_MAP_CACHE
))
762 seq_puts(seq
, ",inode_cache");
766 static int btrfs_test_super(struct super_block
*s
, void *data
)
768 struct btrfs_root
*test_root
= data
;
769 struct btrfs_root
*root
= btrfs_sb(s
);
772 * If this super block is going away, return false as it
773 * can't match as an existing super block.
775 if (!atomic_read(&s
->s_active
))
777 return root
->fs_info
->fs_devices
== test_root
->fs_info
->fs_devices
;
780 static int btrfs_set_super(struct super_block
*s
, void *data
)
784 return set_anon_super(s
, data
);
788 * subvolumes are identified by ino 256
790 static inline int is_subvolume_inode(struct inode
*inode
)
792 if (inode
&& inode
->i_ino
== BTRFS_FIRST_FREE_OBJECTID
)
798 * This will strip out the subvol=%s argument for an argument string and add
799 * subvolid=0 to make sure we get the actual tree root for path walking to the
802 static char *setup_root_args(char *args
)
805 unsigned len
= strlen(args
) + 2;
810 * We need the same args as before, but minus
818 * which is a difference of 2 characters, so we allocate strlen(args) +
821 ret
= kzalloc(len
* sizeof(char), GFP_NOFS
);
824 pos
= strstr(args
, "subvol=");
826 /* This shouldn't happen, but just in case.. */
833 * The subvol=<> arg is not at the front of the string, copy everybody
834 * up to that into ret.
839 copied
+= strlen(args
);
843 strncpy(ret
+ copied
, "subvolid=0", len
- copied
);
845 /* Length of subvolid=0 */
849 * If there is no , after the subvol= option then we know there's no
850 * other options and we can just return.
852 pos
= strchr(pos
, ',');
856 /* Copy the rest of the arguments into our buffer */
857 strncpy(ret
+ copied
, pos
, len
- copied
);
858 copied
+= strlen(pos
);
863 static struct dentry
*mount_subvol(const char *subvol_name
, int flags
,
864 const char *device_name
, char *data
)
866 struct super_block
*s
;
868 struct vfsmount
*mnt
;
869 struct mnt_namespace
*ns_private
;
874 newargs
= setup_root_args(data
);
876 return ERR_PTR(-ENOMEM
);
877 mnt
= vfs_kern_mount(&btrfs_fs_type
, flags
, device_name
,
881 return ERR_CAST(mnt
);
883 ns_private
= create_mnt_ns(mnt
);
884 if (IS_ERR(ns_private
)) {
886 return ERR_CAST(ns_private
);
890 * This will trigger the automount of the subvol so we can just
891 * drop the mnt we have here and return the dentry that we
894 error
= vfs_path_lookup(mnt
->mnt_root
, mnt
, subvol_name
,
895 LOOKUP_FOLLOW
, &path
);
896 put_mnt_ns(ns_private
);
898 return ERR_PTR(error
);
900 if (!is_subvolume_inode(path
.dentry
->d_inode
)) {
904 printk(KERN_ERR
"btrfs: '%s' is not a valid subvolume\n",
906 return ERR_PTR(-EINVAL
);
909 /* Get a ref to the sb and the dentry we found and return it */
910 s
= path
.mnt
->mnt_sb
;
911 atomic_inc(&s
->s_active
);
912 root
= dget(path
.dentry
);
914 down_write(&s
->s_umount
);
920 * Find a superblock for the given device / mount point.
922 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
923 * for multiple device setup. Make sure to keep it in sync.
925 static struct dentry
*btrfs_mount(struct file_system_type
*fs_type
, int flags
,
926 const char *device_name
, void *data
)
928 struct block_device
*bdev
= NULL
;
929 struct super_block
*s
;
931 struct btrfs_fs_devices
*fs_devices
= NULL
;
932 struct btrfs_fs_info
*fs_info
= NULL
;
933 fmode_t mode
= FMODE_READ
;
934 char *subvol_name
= NULL
;
935 u64 subvol_objectid
= 0;
936 u64 subvol_rootid
= 0;
939 if (!(flags
& MS_RDONLY
))
942 error
= btrfs_parse_early_options(data
, mode
, fs_type
,
943 &subvol_name
, &subvol_objectid
,
944 &subvol_rootid
, &fs_devices
);
947 return ERR_PTR(error
);
951 root
= mount_subvol(subvol_name
, flags
, device_name
, data
);
956 error
= btrfs_scan_one_device(device_name
, mode
, fs_type
, &fs_devices
);
958 return ERR_PTR(error
);
961 * Setup a dummy root and fs_info for test/set super. This is because
962 * we don't actually fill this stuff out until open_ctree, but we need
963 * it for searching for existing supers, so this lets us do that and
964 * then open_ctree will properly initialize everything later.
966 fs_info
= kzalloc(sizeof(struct btrfs_fs_info
), GFP_NOFS
);
968 return ERR_PTR(-ENOMEM
);
970 fs_info
->tree_root
= kzalloc(sizeof(struct btrfs_root
), GFP_NOFS
);
971 if (!fs_info
->tree_root
) {
975 fs_info
->tree_root
->fs_info
= fs_info
;
976 fs_info
->fs_devices
= fs_devices
;
978 fs_info
->super_copy
= kzalloc(BTRFS_SUPER_INFO_SIZE
, GFP_NOFS
);
979 fs_info
->super_for_commit
= kzalloc(BTRFS_SUPER_INFO_SIZE
, GFP_NOFS
);
980 if (!fs_info
->super_copy
|| !fs_info
->super_for_commit
) {
985 error
= btrfs_open_devices(fs_devices
, mode
, fs_type
);
989 if (!(flags
& MS_RDONLY
) && fs_devices
->rw_devices
== 0) {
991 goto error_close_devices
;
994 bdev
= fs_devices
->latest_bdev
;
995 s
= sget(fs_type
, btrfs_test_super
, btrfs_set_super
,
999 goto error_close_devices
;
1003 if ((flags
^ s
->s_flags
) & MS_RDONLY
) {
1004 deactivate_locked_super(s
);
1006 goto error_close_devices
;
1009 btrfs_close_devices(fs_devices
);
1010 free_fs_info(fs_info
);
1012 char b
[BDEVNAME_SIZE
];
1014 s
->s_flags
= flags
| MS_NOSEC
;
1015 strlcpy(s
->s_id
, bdevname(bdev
, b
), sizeof(s
->s_id
));
1016 btrfs_sb(s
)->fs_info
->bdev_holder
= fs_type
;
1017 error
= btrfs_fill_super(s
, fs_devices
, data
,
1018 flags
& MS_SILENT
? 1 : 0);
1020 deactivate_locked_super(s
);
1021 return ERR_PTR(error
);
1024 s
->s_flags
|= MS_ACTIVE
;
1027 root
= get_default_root(s
, subvol_objectid
);
1029 deactivate_locked_super(s
);
1035 error_close_devices
:
1036 btrfs_close_devices(fs_devices
);
1038 free_fs_info(fs_info
);
1039 return ERR_PTR(error
);
1042 static int btrfs_remount(struct super_block
*sb
, int *flags
, char *data
)
1044 struct btrfs_root
*root
= btrfs_sb(sb
);
1047 ret
= btrfs_parse_options(root
, data
);
1051 if ((*flags
& MS_RDONLY
) == (sb
->s_flags
& MS_RDONLY
))
1054 if (*flags
& MS_RDONLY
) {
1055 sb
->s_flags
|= MS_RDONLY
;
1057 ret
= btrfs_commit_super(root
);
1060 if (root
->fs_info
->fs_devices
->rw_devices
== 0)
1063 if (btrfs_super_log_root(root
->fs_info
->super_copy
) != 0)
1066 ret
= btrfs_cleanup_fs_roots(root
->fs_info
);
1069 /* recover relocation */
1070 ret
= btrfs_recover_relocation(root
);
1073 sb
->s_flags
&= ~MS_RDONLY
;
1079 /* Used to sort the devices by max_avail(descending sort) */
1080 static int btrfs_cmp_device_free_bytes(const void *dev_info1
,
1081 const void *dev_info2
)
1083 if (((struct btrfs_device_info
*)dev_info1
)->max_avail
>
1084 ((struct btrfs_device_info
*)dev_info2
)->max_avail
)
1086 else if (((struct btrfs_device_info
*)dev_info1
)->max_avail
<
1087 ((struct btrfs_device_info
*)dev_info2
)->max_avail
)
1094 * sort the devices by max_avail, in which max free extent size of each device
1095 * is stored.(Descending Sort)
1097 static inline void btrfs_descending_sort_devices(
1098 struct btrfs_device_info
*devices
,
1101 sort(devices
, nr_devices
, sizeof(struct btrfs_device_info
),
1102 btrfs_cmp_device_free_bytes
, NULL
);
1106 * The helper to calc the free space on the devices that can be used to store
1109 static int btrfs_calc_avail_data_space(struct btrfs_root
*root
, u64
*free_bytes
)
1111 struct btrfs_fs_info
*fs_info
= root
->fs_info
;
1112 struct btrfs_device_info
*devices_info
;
1113 struct btrfs_fs_devices
*fs_devices
= fs_info
->fs_devices
;
1114 struct btrfs_device
*device
;
1119 u64 min_stripe_size
;
1120 int min_stripes
= 1, num_stripes
= 1;
1121 int i
= 0, nr_devices
;
1124 nr_devices
= fs_info
->fs_devices
->open_devices
;
1125 BUG_ON(!nr_devices
);
1127 devices_info
= kmalloc(sizeof(*devices_info
) * nr_devices
,
1132 /* calc min stripe number for data space alloction */
1133 type
= btrfs_get_alloc_profile(root
, 1);
1134 if (type
& BTRFS_BLOCK_GROUP_RAID0
) {
1136 num_stripes
= nr_devices
;
1137 } else if (type
& BTRFS_BLOCK_GROUP_RAID1
) {
1140 } else if (type
& BTRFS_BLOCK_GROUP_RAID10
) {
1145 if (type
& BTRFS_BLOCK_GROUP_DUP
)
1146 min_stripe_size
= 2 * BTRFS_STRIPE_LEN
;
1148 min_stripe_size
= BTRFS_STRIPE_LEN
;
1150 list_for_each_entry(device
, &fs_devices
->devices
, dev_list
) {
1151 if (!device
->in_fs_metadata
|| !device
->bdev
)
1154 avail_space
= device
->total_bytes
- device
->bytes_used
;
1156 /* align with stripe_len */
1157 do_div(avail_space
, BTRFS_STRIPE_LEN
);
1158 avail_space
*= BTRFS_STRIPE_LEN
;
1161 * In order to avoid overwritting the superblock on the drive,
1162 * btrfs starts at an offset of at least 1MB when doing chunk
1165 skip_space
= 1024 * 1024;
1167 /* user can set the offset in fs_info->alloc_start. */
1168 if (fs_info
->alloc_start
+ BTRFS_STRIPE_LEN
<=
1169 device
->total_bytes
)
1170 skip_space
= max(fs_info
->alloc_start
, skip_space
);
1173 * btrfs can not use the free space in [0, skip_space - 1],
1174 * we must subtract it from the total. In order to implement
1175 * it, we account the used space in this range first.
1177 ret
= btrfs_account_dev_extents_size(device
, 0, skip_space
- 1,
1180 kfree(devices_info
);
1184 /* calc the free space in [0, skip_space - 1] */
1185 skip_space
-= used_space
;
1188 * we can use the free space in [0, skip_space - 1], subtract
1189 * it from the total.
1191 if (avail_space
&& avail_space
>= skip_space
)
1192 avail_space
-= skip_space
;
1196 if (avail_space
< min_stripe_size
)
1199 devices_info
[i
].dev
= device
;
1200 devices_info
[i
].max_avail
= avail_space
;
1207 btrfs_descending_sort_devices(devices_info
, nr_devices
);
1211 while (nr_devices
>= min_stripes
) {
1212 if (num_stripes
> nr_devices
)
1213 num_stripes
= nr_devices
;
1215 if (devices_info
[i
].max_avail
>= min_stripe_size
) {
1219 avail_space
+= devices_info
[i
].max_avail
* num_stripes
;
1220 alloc_size
= devices_info
[i
].max_avail
;
1221 for (j
= i
+ 1 - num_stripes
; j
<= i
; j
++)
1222 devices_info
[j
].max_avail
-= alloc_size
;
1228 kfree(devices_info
);
1229 *free_bytes
= avail_space
;
1233 static int btrfs_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
1235 struct btrfs_root
*root
= btrfs_sb(dentry
->d_sb
);
1236 struct btrfs_super_block
*disk_super
= root
->fs_info
->super_copy
;
1237 struct list_head
*head
= &root
->fs_info
->space_info
;
1238 struct btrfs_space_info
*found
;
1240 u64 total_free_data
= 0;
1241 int bits
= dentry
->d_sb
->s_blocksize_bits
;
1242 __be32
*fsid
= (__be32
*)root
->fs_info
->fsid
;
1245 /* holding chunk_muext to avoid allocating new chunks */
1246 mutex_lock(&root
->fs_info
->chunk_mutex
);
1248 list_for_each_entry_rcu(found
, head
, list
) {
1249 if (found
->flags
& BTRFS_BLOCK_GROUP_DATA
) {
1250 total_free_data
+= found
->disk_total
- found
->disk_used
;
1252 btrfs_account_ro_block_groups_free_space(found
);
1255 total_used
+= found
->disk_used
;
1259 buf
->f_namelen
= BTRFS_NAME_LEN
;
1260 buf
->f_blocks
= btrfs_super_total_bytes(disk_super
) >> bits
;
1261 buf
->f_bfree
= buf
->f_blocks
- (total_used
>> bits
);
1262 buf
->f_bsize
= dentry
->d_sb
->s_blocksize
;
1263 buf
->f_type
= BTRFS_SUPER_MAGIC
;
1264 buf
->f_bavail
= total_free_data
;
1265 ret
= btrfs_calc_avail_data_space(root
, &total_free_data
);
1267 mutex_unlock(&root
->fs_info
->chunk_mutex
);
1270 buf
->f_bavail
+= total_free_data
;
1271 buf
->f_bavail
= buf
->f_bavail
>> bits
;
1272 mutex_unlock(&root
->fs_info
->chunk_mutex
);
1274 /* We treat it as constant endianness (it doesn't matter _which_)
1275 because we want the fsid to come out the same whether mounted
1276 on a big-endian or little-endian host */
1277 buf
->f_fsid
.val
[0] = be32_to_cpu(fsid
[0]) ^ be32_to_cpu(fsid
[2]);
1278 buf
->f_fsid
.val
[1] = be32_to_cpu(fsid
[1]) ^ be32_to_cpu(fsid
[3]);
1279 /* Mask in the root object ID too, to disambiguate subvols */
1280 buf
->f_fsid
.val
[0] ^= BTRFS_I(dentry
->d_inode
)->root
->objectid
>> 32;
1281 buf
->f_fsid
.val
[1] ^= BTRFS_I(dentry
->d_inode
)->root
->objectid
;
1286 static struct file_system_type btrfs_fs_type
= {
1287 .owner
= THIS_MODULE
,
1289 .mount
= btrfs_mount
,
1290 .kill_sb
= kill_anon_super
,
1291 .fs_flags
= FS_REQUIRES_DEV
,
1295 * used by btrfsctl to scan devices when no FS is mounted
1297 static long btrfs_control_ioctl(struct file
*file
, unsigned int cmd
,
1300 struct btrfs_ioctl_vol_args
*vol
;
1301 struct btrfs_fs_devices
*fs_devices
;
1304 if (!capable(CAP_SYS_ADMIN
))
1307 vol
= memdup_user((void __user
*)arg
, sizeof(*vol
));
1309 return PTR_ERR(vol
);
1312 case BTRFS_IOC_SCAN_DEV
:
1313 ret
= btrfs_scan_one_device(vol
->name
, FMODE_READ
,
1314 &btrfs_fs_type
, &fs_devices
);
1322 static int btrfs_freeze(struct super_block
*sb
)
1324 struct btrfs_root
*root
= btrfs_sb(sb
);
1325 mutex_lock(&root
->fs_info
->transaction_kthread_mutex
);
1326 mutex_lock(&root
->fs_info
->cleaner_mutex
);
1330 static int btrfs_unfreeze(struct super_block
*sb
)
1332 struct btrfs_root
*root
= btrfs_sb(sb
);
1333 mutex_unlock(&root
->fs_info
->cleaner_mutex
);
1334 mutex_unlock(&root
->fs_info
->transaction_kthread_mutex
);
1338 static void btrfs_fs_dirty_inode(struct inode
*inode
, int flags
)
1342 ret
= btrfs_dirty_inode(inode
);
1344 printk_ratelimited(KERN_ERR
"btrfs: fail to dirty inode %Lu "
1345 "error %d\n", btrfs_ino(inode
), ret
);
1348 static const struct super_operations btrfs_super_ops
= {
1349 .drop_inode
= btrfs_drop_inode
,
1350 .evict_inode
= btrfs_evict_inode
,
1351 .put_super
= btrfs_put_super
,
1352 .sync_fs
= btrfs_sync_fs
,
1353 .show_options
= btrfs_show_options
,
1354 .write_inode
= btrfs_write_inode
,
1355 .dirty_inode
= btrfs_fs_dirty_inode
,
1356 .alloc_inode
= btrfs_alloc_inode
,
1357 .destroy_inode
= btrfs_destroy_inode
,
1358 .statfs
= btrfs_statfs
,
1359 .remount_fs
= btrfs_remount
,
1360 .freeze_fs
= btrfs_freeze
,
1361 .unfreeze_fs
= btrfs_unfreeze
,
1364 static const struct file_operations btrfs_ctl_fops
= {
1365 .unlocked_ioctl
= btrfs_control_ioctl
,
1366 .compat_ioctl
= btrfs_control_ioctl
,
1367 .owner
= THIS_MODULE
,
1368 .llseek
= noop_llseek
,
1371 static struct miscdevice btrfs_misc
= {
1372 .minor
= BTRFS_MINOR
,
1373 .name
= "btrfs-control",
1374 .fops
= &btrfs_ctl_fops
1377 MODULE_ALIAS_MISCDEV(BTRFS_MINOR
);
1378 MODULE_ALIAS("devname:btrfs-control");
1380 static int btrfs_interface_init(void)
1382 return misc_register(&btrfs_misc
);
1385 static void btrfs_interface_exit(void)
1387 if (misc_deregister(&btrfs_misc
) < 0)
1388 printk(KERN_INFO
"misc_deregister failed for control device");
1391 static int __init
init_btrfs_fs(void)
1395 err
= btrfs_init_sysfs();
1399 err
= btrfs_init_compress();
1403 err
= btrfs_init_cachep();
1407 err
= extent_io_init();
1411 err
= extent_map_init();
1413 goto free_extent_io
;
1415 err
= btrfs_delayed_inode_init();
1417 goto free_extent_map
;
1419 err
= btrfs_interface_init();
1421 goto free_delayed_inode
;
1423 err
= register_filesystem(&btrfs_fs_type
);
1425 goto unregister_ioctl
;
1427 printk(KERN_INFO
"%s loaded\n", BTRFS_BUILD_VERSION
);
1431 btrfs_interface_exit();
1433 btrfs_delayed_inode_exit();
1439 btrfs_destroy_cachep();
1441 btrfs_exit_compress();
1447 static void __exit
exit_btrfs_fs(void)
1449 btrfs_destroy_cachep();
1450 btrfs_delayed_inode_exit();
1453 btrfs_interface_exit();
1454 unregister_filesystem(&btrfs_fs_type
);
1456 btrfs_cleanup_fs_uuids();
1457 btrfs_exit_compress();
1460 module_init(init_btrfs_fs
)
1461 module_exit(exit_btrfs_fs
)
1463 MODULE_LICENSE("GPL");